/*
 [The "BSD license"]
 Copyright (c) 2011 Terence Parr
 All rights reserved.

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions
 are met:

 1. Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
 2. Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in the
    documentation and/or other materials provided with the distribution.
 3. The name of the author may not be used to endorse or promote products
    derived from this software without specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.antlr.v4.automata;

import org.antlr.v4.runtime.atn.ATN;
import org.antlr.v4.runtime.atn.ATNState;
import org.antlr.v4.tool.ast.ActionAST;
import org.antlr.v4.tool.ast.BlockAST;
import org.antlr.v4.tool.ast.GrammarAST;
import org.antlr.v4.tool.ast.PredAST;
import org.antlr.v4.tool.ast.TerminalAST;

import java.util.List;

public interface ATNFactory {
	/** A pair of states pointing to the left/right (start and end) states of a
	 *  state submachine.  Used to build ATNs.
	 */
	public static class Handle {
		public ATNState left;
		public ATNState right;

		public Handle(ATNState left, ATNState right) {
			this.left = left;
			this.right = right;
		}

		@Override
		public String toString() {
			return "("+left+","+right+")";
		}
	}

	ATN createATN();

	void setCurrentRuleName(String name);

	void setCurrentOuterAlt(int alt);

	Handle rule(GrammarAST ruleAST, String name, Handle blk);

	ATNState newState();

	Handle label(Handle t);

	Handle listLabel(Handle t);

	Handle tokenRef(TerminalAST node);

	Handle set(GrammarAST associatedAST, List<GrammarAST> alts, boolean invert);

	Handle charSetLiteral(GrammarAST charSetAST);

	Handle range(GrammarAST a, GrammarAST b);

	/** For a non-lexer, just build a simple token reference atom.
	 *  For a lexer, a string is a sequence of char to match.  That is,
	 *  "fog" is treated as 'f' 'o' 'g' not as a single transition in
	 *  the DFA.  Machine== o-'f'->o-'o'->o-'g'->o and has n+1 states
	 *  for n characters.
	 */
	Handle stringLiteral(TerminalAST stringLiteralAST);

	/** For reference to rule r, build
	 *
	 *  o-e->(r)  o
	 *
	 *  where (r) is the start of rule r and the trailing o is not linked
	 *  to from rule ref state directly (it's done thru the transition(0)
	 *  RuleClosureTransition.
	 *
	 *  If the rule r is just a list of tokens, it's block will be just
	 *  a set on an edge o->o->o-set->o->o->o, could inline it rather than doing
	 *  the rule reference, but i'm not doing this yet as I'm not sure
	 *  it would help much in the ATN->DFA construction.
	 *
	 *  TODO add to codegen: collapse alt blks that are sets into single matchSet
	 * @param node
	 */
	Handle ruleRef(GrammarAST node);

	/** From an empty alternative build Grip o-e->o */
	Handle epsilon(GrammarAST node);

	/** Build what amounts to an epsilon transition with a semantic
	 *  predicate action.  The pred is a pointer into the AST of
	 *  the SEMPRED token.
	 */
	Handle sempred(PredAST pred);

	/** Build what amounts to an epsilon transition with an action.
	 *  The action goes into ATN though it is ignored during analysis.
	 */
	Handle action(ActionAST action);

	Handle action(String action);

	Handle alt(List<Handle> els);

	/** From A|B|..|Z alternative block build
     *
     *  o->o-A->o->o (last ATNState is blockEndATNState pointed to by all alts)
     *  |          ^
     *  o->o-B->o--|
     *  |          |
     *  ...        |
     *  |          |
     *  o->o-Z->o--|
     *
     *  So every alternative gets begin ATNState connected by epsilon
     *  and every alt right side points at a block end ATNState.  There is a
     *  new ATNState in the ATNState in the Grip for each alt plus one for the
     *  end ATNState.
     *
     *  Special case: only one alternative: don't make a block with alt
     *  begin/end.
     *
     *  Special case: if just a list of tokens/chars/sets, then collapse
     *  to a single edge'd o-set->o graph.
     *
     *  Set alt number (1..n) in the left-Transition ATNState.
     */
	Handle block(BlockAST blockAST, GrammarAST ebnfRoot, List<Handle> alternativeGrips);

//	Handle notBlock(GrammarAST blockAST, Handle set);

	/** From (A)? build either:
	 *
	 *  o--A->o
	 *  |     ^
	 *  o---->|
	 *
	 *  or, if A is a block, just add an empty alt to the end of the block
	 */
	Handle optional(GrammarAST optAST, Handle blk);

	/** From (A)+ build
	 *
	 *     |---|    (Transition 2 from A.right points at alt 1)
	 *     v   |    (follow of loop is Transition 1)
	 *  o->o-A-o->o
	 *
	 *  Meaning that the last ATNState in A points back to A's left Transition ATNState
	 *  and we add a new begin/end ATNState.  A can be single alternative or
	 *  multiple.
	 *
	 *  During analysis we'll call the follow link (transition 1) alt n+1 for
	 *  an n-alt A block.
	 */
	Handle plus(GrammarAST plusAST, Handle blk);

	/** From (A)* build
	 *
	 *     |---|
	 *     v   |
	 *  o->o-A-o--o (Transition 2 from block end points at alt 1; follow is Transition 1)
	 *  |         ^
	 *  o---------| (optional branch is 2nd alt of optional block containing A+)
	 *
	 *  Meaning that the last (end) ATNState in A points back to A's
	 *  left side ATNState and we add 3 new ATNStates (the
	 *  optional branch is built just like an optional subrule).
	 *  See the Aplus() method for more on the loop back Transition.
	 *  The new node on right edge is set to RIGHT_EDGE_OF_CLOSURE so we
	 *  can detect nested (A*)* loops and insert an extra node.  Previously,
	 *  two blocks shared same EOB node.
	 *
	 *  There are 2 or 3 decision points in a A*.  If A is not a block (i.e.,
	 *  it only has one alt), then there are two decisions: the optional bypass
	 *  and then loopback.  If A is a block of alts, then there are three
	 *  decisions: bypass, loopback, and A's decision point.
	 *
	 *  Note that the optional bypass must be outside the loop as (A|B)* is
	 *  not the same thing as (A|B|)+.
	 *
	 *  This is an accurate ATN representation of the meaning of (A)*, but
	 *  for generating code, I don't need a DFA for the optional branch by
	 *  virtue of how I generate code.  The exit-loopback-branch decision
	 *  is sufficient to let me make an appropriate enter, exit, loop
	 *  determination.  See codegen.g
	 */
	Handle star(GrammarAST starAST, Handle blk);

	/** Build an atom with all possible values in its label */
	Handle wildcard(GrammarAST associatedAST);

	/** Build a subrule matching ^(. .*) (any tree or node). Let's use
	 *  (^(. .+) | .) to be safe.
	 */
	Handle wildcardTree(GrammarAST associatedAST);

	Handle lexerAltCommands(ATNFactory.Handle alt, ATNFactory.Handle cmds);

	String lexerCallCommand(GrammarAST ID, GrammarAST arg);

	String lexerCommand(GrammarAST ID);
}
